Manufacture of phosphorus and calcium carbid.



No. 862,092. PATENTED JULY 30, 1907.

J. T. MOREHEAD.

MANUFAGTURE OF P'HOSPHORUS AND CALCIUM GARBID.

APPLIOATION FILED ooT.14, 1895.

WITNESSES: INVENTOR:

By /u's AMW/lays,

UNITED STATESr PAFIEN'Il OFFICE.

JAMES TURNER MOREHEAD, OF LEAKSVILLE, NORTH CAROLINA, ASSIGNOR, BY MESNEASSIGNMENTS, TO WILLSON LABORATORY COMPANY, OF NEW YORK, N. Y., A CORPO-RATION OF WEST VIRGINIA.

MANFACTURE OF PHOSPHORUS AND CALCIUM CARBID.

Specification of Letters Patent.

Patented July 3o, 1907.

Application filed October 14,1895. Serial N0. 565,638.

. citizen of the United States, residing at Leaksville, in

the county o Rockingham and State of North Carolina, have inventedcertain new and useful Improvements in the Production of Phosphorus andCalcium Carbid, of which the following is a specification.

This invention provides an improved process for the production ofphosphorus from, a phosphate of a metallic base. It is distinguished bythe formation of metallic carbids from the metallic bases of suchphosphates, the phosphorus being reduced and driven off during theoperation. f

My invention provides a direct method of producing phosphorus at asingle operation from calcined bones, phosphate rock, (for examplephosphate of lime, phosphate of iron, and phosphate of alumina), orother phosphorus compounds.

According to my invention I place in a furnace or retort a phosphate ofa metallic base (as calcined and ground bones or ground phosphate rocketc.) with a sufficient proportion of carbon to serve not only as areducing agent for the phosphoric acid, but also to reduce the metallicoxid base, and subject the same to so'high a degree of heat as to notonly decompose and reduce the phosphate, but also to reduce the metallicoxd and produce a carbid of the metallic base. The phosphorus which isthus freed, distils over from the retort and is condensed by passing itunder water in the usual manner. For attaining the requisite degree ofheat, I use the heat generated-by the electric arc, the retort beingconstructed as 'an electric furnace. The process thus becomes one ofelectric smelting. In practice, I may employ a phosphate rock consistingchiefiy of tricalcic phosphate, andA I employ powdered carbon and ahydrocarbon gas asthe reducing agents,

the resultants of the process being carbon monoxid which passes throughthe` condenser and is burned, phosphorus which is arrested in thecondenser, and calcium carbid which remains in the furnace, with alsosome by-products due to the presence of other ingredients in thephosphate rock than the mere tricalcic phosphate. Ordinary 'phosphaterock contains ap- 7 or 8 per cent insoluble silicious'matter.

In practicing my process I take 100 pounds of such phosphate rock andadd to it pounds or thereabouts of carbon in the form of coke, charcoal,or any other `55 suitable form, and I grind the two together to theconsistency of a fine powder or Hour. I may add 8 pounds or thereaboutsof lime for the purpose of taln'ng up the silicious matter in thephosphate roclc, but this is not Y essential to my invention and may beomitted. I may also add alsmall proportion of finely ground .sand orother form of silica if found desirable, in order to form a slag foreliminating any by-products, but this will be determined by theparticular composition of the phosphate rock. These ingredientsintimately mixed together are placed in the chamber, retort or Crucibleof an electric furnace, and the outlet or blow-hole thereof is connectedby a tube to a condenser, so that the gaseous or vaporous mattersdischarged from the furnaceI are carried under water into a closedvessel, whereby the phosphorus which distils over may be condensed.

The carbon monoxid which passes over into the condenser bubbles upthrough the Water and escapes through an outlet at the top, Where it ispreferably ignited. In addition a reducing gas, such as ordinaryilluminating gas, or other hydrocarbon gas, is caused to flow throughthe furnace, its flow being commenced before the beginning of thesmelting, to expel all air or oxygen. The electric smelting action isbelieved to be due primarily to the high degree of heat, andsecondarily, to the presence of the carbon as a reducing agent whichunites with the calcium by having a higher aflinity therefor than theoxygen or phosphorus, whereby the calcium is converted into calciumcarbid, and the phosphoric oxid which is disengaged is reduced freeingthe phosphorus, which is vaporized and distils over. The operation isbelieved to be in accordance with the following equation which is welladapted for practicing my invention, and

which to the best of my present lmowledge and experience is thepreferable one for the purpose.

The figure is a vertical longitudinal section through the apparatus, theelectric circuit and dynamo being shown diagrammatically.

' the other electrode.

Let A designate the bench or brickvy'orkl of the furnace, VB theCrucible or hearth thereof/'made of carbon or graphite, C thecarbon slab,covering the furnace, D the carbon pendil constituting'one'ef theelectrodes. and E thedynamo by which the electric energy is generated.One terminal of the dynamo is connected by a wire a with the carbonpencil D, and the other terminal is connected by a wire b with a plateor slab c beneath the carbon Crucible B, and by which an extendedsurface of (contact is obtained for the passage of the current. fromthis plate to thc Crucible, so that-the latter constitutes If acontinuous current is emi ployed, thecarbon pencil should` be thecathode, but I believe an alternating current to be preferable. Toprevent the escape of gases or vapors from the furnace, a 4luting d of"ireclay is interposed between the cover C and the top 0f the bench,which luting also serves as' an insulator. To preventthe escape ofvapors through the opening in the cover, through which opening thepencil passes, and which openingmust be so 'free as to permit of theeasy adjustment of the pencil up or down for controlling the arc, Iprovide a sort of 'stuffing-box e, which upon'ithese, and .finally thewhole is covered with carbon fiour or finely ground carbon; Thisconstruction is sulicient in the absence of any material pressuren the lchamber orretort of the furnace, to'prevent the escape of vapors orgases therefrom. In place of the usual blowhole for permitting theescape of' gases and vapors, I providea tubular outlet g` of somerefractory material,

l such as freclay or lime,fwliich preferably terminates upwardly and isextended by a tube or neck 'of lireclay i which extends up and thendownl and is connected Aware, in one or more sections, which tubeextends into the condenser F; Vbeing luted atv '17 where it entei's-itso as to make a tight joint... These lutings are effected with clay orlime, or any other substance 'unaffected by car- -bon.`r`nonoxid orphosphorus. The tube 'movable cap g2 to enable it to be cleaned out. Itis preferable that the pipe 'i shall dip to a consider# g llas a re.-

l .ablev depth-beneath the water in the condenser F, which would havethe effect of maintaining a considerable 5,0

c k pressure in the retort, andt avoid this, as Well as valve j. Bysuitably adjusting this valve, the pressure can be -so 4regulated as texactly-counterbalance the hydrostatic-pressure in thegcondenser,softhat the pressure shall: be. equal irtherretort to the atmosphericpressure exterior thereto,'.as shown by the liquid gage p.

The, red'ucin'g gas-is introduced'by a pipe Aq from a generator 'or gasholder and-is heated by passing through the furnace wall before being`injected i'nto the furnace chamber. In condenser F, the phosphorus whichis condensed passes to the bottom of the water, and theuncondensedv-phosphorus in connection with the hydrocarbon gases isarrested by a submerged plate lc,

may be of any construction heretofore known for densing'phosphorusvapors.

by a lutsdjoim a h with @tube i preferablyf earthen to` assist -in thecondensation ot therplyiosphorus ani'lffthecooling ofthe hydrocarbongases, I provide for showering water into the tube from a pipeG'controlledby a ts/sacas which may be of glass, earthenware' orsuitably coated metal, along which they must pass and continue incontact with the water until they reach its margin, when the gasesbubble up and escape above the water, the phosphorus by this time havingbeen entirely condensed. The gases pass out through a tube l as usual,and are ignited and burn as they issue therefrom. In starting thevoperation the air originally in `the"con denser F above the water levelshould be displaced by. filling it with carbonio acid gas, or otherwise,so that there can be no oxidation of any phosphorus which may float uponthe water. The Water which is continually admitted' from the pipe G,together with any water which is displaced by the accumulation ofthephosphorus, escapesg by a sealed overflow, m. i'

f The phosphorus which is condensed in the wateris intermixed with someimpurities, chiefly particles of unreduced phosphate and carbon, whichare easily i separated by fusing the phosphorus under `water andpressing it out from the foreign matters, in the well known manner, andsubsequently the phosphorus may be further purified by treatment withpotassium dichromate and sulfuric acid as heretofore practicedf.-

It will be understood that this apparatus may-.be greatly varied withoutdeparting from the essential features of `my invention. For example, Lam not limited to the employment of a stream-.or shower ofY Waterentering the condenser, as this may be omitted. Nor am: I limited to themeans shown for packing or luting around the, carbon pencil. Thecondenser F con- Theessentials o'my process I believe to be theemployrnentiofI a'higl'r degree of heat in connection: with an abundantexcess of a carbonaceous reducing agent, to combine withy thecalcium, ormetallic base to form a metallic carbid, and this or some otherequivalent reducing agent (as hydiio'gen)y to combine with the oxygen ofthe phosphoric acid; My process of electric smelt-ing may =be applied inhe production of phosphorus from: other compounds,

such afs-phosphate of alumina.

'lhe calcium` or other metallic carbid produced'by my process isavaluable'by-product andE may bet used as a source of acetylenegas.

Iam aware that processes have Vheretofore beenl patf.

ent'edi for thamanufactur. off-'phosphorus by treating a'phosphate withcarbon: inv an electric furnace, and condensing the resulting phosphorusvapor. InV such processes,.howev er, there has-been no production of acarbid. of" the) metallic base of the`phosphorus com-` pound, the carbonemployed being sufficient in quantity only: -for liberating thephosphorus from the phosphoricacid, and not being sufiicient to reducethev l calcium (or other) oxid to form a carbid. 'The result islthatwith the processes referred to the residue remaining in the furnaceiisa. valueless slag, whereas in my process it isa valuable carbid'.Hencemy'process is essentially distinguishedv from said previousprocasses bythe employment' of a greater proportion of carbon, in ordernot only to reduce the phosphoric acid, but also sufcientto combine withthe oxygen of the metallic oxid, and also with the reduced metal -toform a carbid therewith. The essential difference in the case of a.Vtribasic calcium phosphate between my process and those heretoforepatented, Will be apparent upon a comparison oi the equationhereinbefore given illustrating the reaction in my process, and thefollowing equatif'n Which illustrates the reaction according to saidprevious processes, namely:-

The calcium carbid produced by my process may contain calcium phosphidintimately combined therewith by the smelting operation7 especially incase the carbon is insufficient and the smelting operation is notsufficiently prolonged. While ordinarily it is desirable to avoid thepresence of such phosphid, yet a carbid containing such phosphid hascertain properties Which may render it desirable for certain uses, Suchcarbid containing phosphid7 on being treated With Water generatesacetylene `and hydrogen phosphid, and the latter ienites spontaneously,thus igniting the acetylene, As a possible use for such product l willsuggest that in case it should become desirable to illuminate a distantpoint on a body of Water at night7 a cartridge or` shell charged Withthis material might be fired` from a gun under such conditions as toliberate the material on striking the Wat-er. The carbid Would theninstantly begin to generate acetylene gas, which would be ignited by thephosphid, and if the mass Were made to float, the reaction wouldcontinue until all the carbid was decomposed, so that a brilliantillumination could be maintained for a considerable time, depending onthe rapidity with Which Water were admitted to the carbid. Other usesfor this neW- product will doubtless suggest themselves in course ot'time.

I claim as my invention the following defined novel featuressubstantially as hereinbeforc specifiedJ namely:-

1. The process of producingr phosphorus and a metallic carbid. whichconsists in subjecting to beat a phosphate of a metallic base with areducing agent for the phosphorc acid and an abundant excess of carbon.the heat being suiciently intense to set free phosphorus and to causethe metallic hase to combine with carbon forming' a metallic carbid.

2. The process of producing phosphorus and a metallic. carbid. whichconsists in subjecting to electric smcliing: a phosphate of a metallicbase with :1 reducingr acont for the phosphoric acid and an abundantexcess of carbon to combine with the metallic base. whereby phosphorusis sci; free and a metallic carbid is formed.

5%. 'lhe process of producing,r phosphorus and :i metallic carbid. whichcons ts iu subjecting to electric smelting iu a closed chamber calciumphosphate with a reducing agent for the phosphoric acid and an abundantexcess of carbon to combine with the calcium to form calcium carbid, andcondensing the resultant vapors.

4. The process of producingr phosphorus and a metallic carbid. whichconsists in subjectingr calcium phosphate with carbon and lime toelectric smcltiuf,r in :i closed chambei'` the carbon beinel insuthcient proportion to combine with the calcium io form calcium carbid.:ind condensing the resultant vapors.

ln witness whereof. l have hereunto signed my name in the presence oftwo subscribing witnesses.

JAMES TURNER MOREHEAD.

Witnesses:

.loHN WILSON, il. C. Cnamulcn'r.

